Passenger vehicle transport capacity is an important design aspect of modern vehicles. The ability to haul objects and equipment is often as important as the vehicle's ability to transport additional passengers. Solutions aimed at increasing a vehicle's hauling capabilities must not only be directed at improving the vehicle's utility but must also be directed towards improving a vehicle's safety and performance while accomplishing this task. One traditional approach towards improving a vehicle's transport capabilities has been through the addition of a trailer attached to the vehicle. Trailers allow for a wide range of items to be transported by a vehicle, often without impacting transport capabilities of the vehicle's passenger compartment.
Where a passenger vehicle serves as a tow vehicle, trailer braking is often controlled through the use of a trailer brake controller located within the tow vehicle. The trailer is commonly equipped with a brake system that includes electrically actuated trailer brakes. A driver of the tow vehicle sets the gain on the trailer brake controller, where the gain dictates how much electrical output is generated by the trailer brake controller for a given set of vehicle inputs. The trailer brake controller utilizes a brake input signal in combination with the user set gain to generate a brake control signal. It is known that this signal can take different forms, such as a duty cycle output or DC voltage output. This control signal is sent to the trailer brake system via a wiring harness and is utilized by the trailer brake system to effectuate braking by the electrically actuated trailer brakes of the trailer brake system. Systems such as described translate vehicle input, such as brake pedal force or position, brake pressure or vehicle acceleration, into a brake control signal which is adjustable according to the operator set gain. The brake-actuating output signal, in turn, energizes the trailer brakes, which subsequently generates a braking torque on the trailer wheels.
Although the aforementioned systems can benefit from a lack of complexity, they fail to address the real world principles of mechanics that electrically actuated trailer brake assemblies are subject to. It is well-known that a brake torque desirable over a broad range of vehicle speeds can be undesirable at low vehicle speeds. At low vehicle speeds, electrically actuated braking systems, which are typically of the dual-servo drum type, generally exhibit a significant increase in effectiveness wherein an applied brake torque can result in the brakes locking up (also known as “grabbiness”) rather than incrementally applying braking friction. To reduce the potential for such grabbiness at relatively low speeds, some known trailer brake controllers (i.e., conventional trailer brake controllers) are configured to provide a speed-dependent brake-actuating output signal when the tow vehicle slows below a certain speed. This speed-dependent brake-actuating output signal is intended to provide smooth braking (i.e., less grabbiness) at lower speeds. However, at standstill, implementation of a speed-dependent brake-actuating output signal in this manner results in the trailer brake controller providing less than maximum possible or desirable output, which can lead to the tow vehicle brakes having to exert an undesirable amount of brake torque to hold the tow vehicle/trailer at a standstill. Furthermore, in certain situations such as, for example, when at a standstill on an inclined surface, the reduced brake torque at the trailer resulting from the speed-dependent brake-actuating output signal can adversely impact the ability of the combined brake systems of the tow vehicle/trailer combination to provide sufficient or desirable brake torque to maintain the tow vehicle/trailer combination at a standstill.
Therefore, configuring speed-dependent brake-actuating output signal functionality of a trailer brake controller to provide a brake-actuating output signal that is in excess of a brake-actuating output signal of a conventional trailer brake controller when the vehicle is detected to be at a standstill and braking is being requested by the driver would be advantageous, desirable and useful.